The present invention relates to a flat plate type heat exchanger.
Energy-saving is promoted, and there are demands for improving thermal efficiency, for saving electric power by recovering waste heat, and for reducing an amount of fuel consumption.
In order to respond to the demands as described above, efforts are now being made to improve thermal efficiency by incorporating a heat exchanger in a system or to recover a waste heat by installing a heat exchanger on an exhaust gas line.
The present applicant proposed a heat exchanger as disclosed in the Japanese Patent Publication JP-A-2012-117631. According to the heat exchanger disclosed in the patent publication, projections are formed on a flat plate at a distribution ratio as required, and the flat plate is folded, back in multilayers alternately with such width as required, and a gap for she projection is formed between the flat plates, and heat transfer unit is arranged with the flat plates as boundaries. A high temperature fluid and a low temperature fluid are passed through the gap, and heat exchange is carried out via the heat transfer unit.
The heat exchanger is advantageous in that the heat exchanger as designed in simple construction and available at low cost, and that the heat exchanger has high thermal efficiency and is convenient in its maintainability. Meanwhile, the heat exchanger as described above did not have high air-tightness and high pressure-tightness to the fluid, which is the object of heat exchange.